Direct Evidence of Intrinsic Mott State and Its Layer-Parity Oscillation in a Breathing Kagome Crystal Down to Monolayer

作者：Huanyu Liu, Wenhui Li, Zishu Zhou, Hongya Qu, Jiaqi Zhang, Weixiong Hu, Chenhaoping Wen, Ning Wang, Hao Deng, Gang Li, Shichao Yan · 发表于：Physical Review Letters · 年份：2025 · DOI：10.1103/mzyy-thjq · 被引用次数：6 · 研究领域：Advanced Condensed Matter Physics、Topological Materials and Phenomena、Physics of Superconductivity and Magnetism

We report direct spectroscopic evidence of correlation-driven Mott states in layered Nb_{3}Cl_{8} through combining scanning tunneling microscopy (STM) and dynamical mean-field theory. The Hubbard bands persist down to monolayer, providing the definitive evidence for the Mottness in Nb_{3}Cl_{8}. While the size of the Mott gap remains almost constant across all layers, a striking layer-parity-dependent oscillation emerges in the local density of states (LDOS) between even (n=2, 4, 6) and odd layers (n=1, 3, 5), which arises from the dimerization and correlation modulation of the obstructed atomic states, respectively. Our conclusions are supported by a critical technical advance in atomic-scale LDOS mapping for highly insulating systems. This Letter provides the definitive experimental verification of correlation-driven Mott ground states in Nb_{3}Cl_{8}, while establishing a general protocol for investigating the interplay of electronic correlation and interlayer coupling in layered insulators by using a low-temperature STM technique.